144 patients operated on for trigeminal neuralgia between June 1982 and May 1990 were followed for up to 8 years. 122 patients were treated by retrogasserian glycerol rhizolysis and 22 by posterior fossa exploration. The average age was 65 years. 89 patients were women and 55 men. The 1st branch was principally involved in 9 patients, the 2nd in 92 and the 3rd in 43. 32 patients had prior procedures. 102 of the 122 patients submitted to glycerol injection were rendered pain-free (84%). An additional 7 patients were relieved by a supplemental radiofrequency procedure, thus achieving an 89% success rate with the percutaneous approach. All 22 posterior fossa explorations were initially successful. 65 patients of the group treated percutaneously had some new postoperative objective and/or subjective sensory deficit as well as 13 of the patients operated on by posterior fossa exploration. Corneal sensation was decreased after 19 glycerol procedures including 3 who had a supplemental radiofrequency coagulation. No corneal hypaesthesia was seen after posterior fossa explorations. Kaplan-Meier analysis showed that at 5 years 59% of the percutaneous rhizolysis group were free of neuralgia and 68% of the patients treated by posterior fossa exploration. A number of patient characteristics and surgical factors were analysed for a possible correlation with outcome. Intact preoperative facial sensation was the most important prognostic factor for an initially successful operative result. Some degree of postoperative sensory deficit was the most important factor for long-term remission of neuralgia. However, of the 54 patients with a postoperative new sensory deficit who were available for long-term follow-up, 13 complained of persistent disturbing disaesthesias.